DESCRIPTION (Applicant's abstract): In this application we propose to advance the work of developing safe and effective prevention services to combat the epidemic of HIV and sexually transmitted infections among men with severe mental illness. We will conduct a randomized clinical trial of a sexual risk reduction intervention among at-risk, inner- city men with severe mental illness attending outpatient psychiatric clinics. The intervention is theory-based and preliminary data suggest efficacy. We also propose to gather descriptive epidemiological data on the prevalence and incidence of gonorrhea and chlamydia among the men enrolled in the clinical trial. Such infections impact on the health of the severe mentally ill and place them at greater risk of HIV infection. The data will enable mental health providers to assess the value of incorporating the diagnosis and treatment of sexually transmitted infections into the routine care of men with severe mental illness. The clinical trial will enroll 200 men and follow them for 24 months. The trial is designed to minimize potential biases and accurately assess both short-term and long-term efficacy of the intervention. The primary outcome will be self-reported sexual risk behavior. Trends in the incidence of sexually transmitted infections will be used for corollary evidence of an intervention effect. We will thoroughly examine the implications of the data for service provision and disseminate the results as appropriate.